▎ 摘　　要

A nanohybrid magnetic fluorescent sensing probe was designed and fabricated for ultrasensitive and selective determination of levofloxacin. The probe integrated porous graphene (PGr), magnetite (Fe3O4) nanoparticles and graphene quantum dots (GQDs) into selective molecularly imprinted polymer (MIP). The developed probe was sensitive, selective, and its binding ability enriched levofloxacin in complex samples. The fabrication strategy was evaluated to achieve the best performance and the synthesized sensing probe was characterized. In the best condition, the fluorescence emission of the probe was quenched linearly from 0.10 to 25.0 mu g L-1 of levofloxacin and the limit of detection was 0.03 mu g L-1. The quenching of fluorescence was not affected by the analog compounds ciprofloxacin, lomefloxacin, marbofloxacin and sarafloxacin. The imprinting factor of the developed nanohybrid sensing probe was 4.26. The developed probe was utilized to detect levofloxacin in milk and recoveries between 91.8 % and 100.5 % were achieved with RSDs <6.5 %. Analysis with the optosensor provided the same results as HPLC analysis but the optosensor was more sensitive, less expensive, simpler and more rapid. (C) 2021 Elsevier B.V. All rights reserved.